I just quit my job midweek and a system was entering the
plains on Thursday, which made it perfect for a two day trip out to the
plains. The day featured strong instability and great directional
shear from a very deep surface over Colorado, but the speed shear was
forecast to be on the light side. This was the "day before the day"
chase with Friday forecast to be a major outbreak. Chad, Ben, and I
left the suburbs bright and early and trekked west on 80 targetting
somewhere in southeast Nebraska. |
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We took a slight detour south of Des Moines after
distracting Chad with maxed out forecasted tornado parameters. As we
crossed the Nebraska border and got back onto 80 near Grand Island, storms
started to fire right over head. We went for more mature storms
to our northwest that were already warned. We caught a view of the
base as we approached Ravenna: |
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There was heavy precipitation in the storm's updraft base,
and it was exhibiting high precipitation supercell characteristics. As
it started to congeal into a line with other nearby cells, we dropped south
towards Kearney for a more discrete storm. |
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Just south of Kearney, our storm's base came into view, and
it was quite a sight. The storm had a very large rain free base,
brilliant contrast, and two areas of rotation. The storm went tornado
warned as we setup our tripods to shoot its approach. |
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Looking west: |
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Huge bell shaped meso: |
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As the supercell approached some rain curtains started to
fall through the base. Rotation was observed in these rain bands, just
to the right of the telephone pole: |
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The rain free base approached from the west with amazing
contrast: |
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The rear flanking downdraft cuts through the storm, bowing
the the base out forward: |
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We let the base pass overhead and noted lots of churning
motion, but no tight areas of rotation. We got out ahead of the storm
just across the river and stopped for more pictures of the base: |
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A bowl shaped bulge in the storm's updraft base: |
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We stayed ahead of the storm as it started to lose strength
and its warnings. The updraft tower starting to become elevated and
evaporate away from the ground: |
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We stopped east of Kearney for more pictures. The
supercell completely abandoned its updraft base which had bowed out into
more of a gust front, leaving behind a very dramatic roll cloud: |
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Looking west at the lifting storm and orphaned roll cloud
below: |
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Looking southwest: |
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As the roll cloud spread out to the east, it too started to
evaporate. On the north end of it, however, strange tentacle like
tendrils of cloud started to condense on the leading edge. I had never
seen anything like it before. |
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The tentacles appeared to be an inflow related feature, but
I'm not entirely sure what processes are behind this unusual formation. |
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After stopping for some grub in Grand Island, a mean looking
severe warned line started to go up on the NE/KS border. We went south
to intercept it, not expecting any tornado potential, just a good lightning
show, and the lightning was indeed fantastic. Punching through the
line without encountering more than a smattering of pea sized hail, we
stopped for the night in Belleville, KS. |
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Conclusion: There were no tornadoes on
this chase, but the supercell structure was fantastic, and it was a great
opener to a two day event. The storm we wound up targeting was in the
middle of two more tornado clusters of storms, but southwest Iowa turned out
to be the most prolific tornado producing area. |
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Lessons Learned:
- Don't distract Chad with Rich Thompson's index when he's driving.
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